Janov Reservoir, National cultural monument and lake in Lounice, Czech Republic

Janov Reservoir, also called Hamerská or Mostecká přehrada, is a gravity dam of quarry-stone masonry in the Hamerské údolí valley below Křížatky. Its crest is 226 m long and 4.5 m wide, the wall 43 m high; the lake holds 1.65 million m³ over 10 hectares at 448 m above sea level, built on the Intze principle.

The reservoir was built in 1911 to provide flood protection and create a sustainable water management system for the surrounding region. This engineering project has shaped the landscape and water transport in the area ever since.

The reservoir serves as a gathering place where locals and visitors come to experience nature and enjoy the shoreline for leisure activities. Its status as a protected monument reflects how this location has become woven into the region's sense of place over time.

The dam lies in zone I of hygienic protection, so the dam crest, the access road and the areas around the reservoir are closed to the public; the site can only be viewed from outside. The reservoir has been drawn down since about 2007 for rehabilitation, including a new inspection gallery and bottom outlet. The dam is 43 m high, its crown 226 m long and 4.5 m wide.

The dam is a gravity wall of quarry-stone masonry built on the Intze principle, 43 m high with a 226 m long, 4.5 m wide crown. The reservoir has been drawn down since about 2007 for rehabilitation, including a new inspection gallery and bottom outlet.